I am a science nerd, but I am also religious. I think that humans are definitely pushed by biological needs. But if that was our only drive, we would have stopped a long time ago. 

As for the other two options, both are viable. Our agency, our free will, drives all people forward. Each person's agency is different, of course, but generally, I think humans have agency's that strive for something better. This is what has let us progressed so far.

I do think there is a Virtue, but I believe this "external good" as you called it is just as much internal as it is external. The way I see things, the virtue of God that exists externally also exists within every person, to a degree. I believe that as God's children, his divine nature is in each of us. That universal virtue, combined with our free will and our daily biological needs, is what drives us forward to progress and grow.

I didn't mean to wax religious there at the end. I realize that not all people will share all my viewpoints, so feel free to share yours or argue against mine below. 

I do.

Frustration is the motivator for all improvement. The stubborn refusal of humanity to simply accept what it is and where it is at. Everytime a man desires more for life, wishes something came a little bit easier, I bring it to pass. Everytime someone wants to know what lies beyond the next hill the reason is that they are tired, Frustrated by only knowing what they have, by being confined to what they are. Anytime an improvement has been made in science, technology, communication, government, exploration, philosophy, math, exploration, it is only through me, by me, because of me. I am what makes men, men. I am Frustration.